Bank multiple contact structure for telephone switching mechanisms



Aug. 28, 1956 w. LOHS EIAL BANK MULTIPLE CONTACT STRUCTURE FOR TELEPHONESWITCHING MECHANISMS 2 Sheets-Sheet 1 Filed Feb. 28, 1952 ruth H. EH13 0Lmuff ufrffm J jmvezz zjgns. W JO 6] wdi mwen W562 ezdeaj. J W

g- 1956 w. LOHS ETAL 2,761,013

BANK MULTIPLE CONTACT STRUCTURE FOR TELEPHONE SWITCHING MECHANISMS FiledFeb. 28, 1952 2 Sheets-Sheet 2 a 0145, faded? Jammer, Z hjerfireza-ifezf United States Patent BANK MULTIPLE CONTACT STRUCTURE FORTELEPHONE SWITCHING MECHANISMS Willy Lohs, Berlin-Siemensstadt,Friedrich Sommer,

Berlin-Nikolassee, and Walter Breustedt, Berlin-Charlottenhurg, Germany,assignors to Siemens 8; Halslte Aktiengesellschaft, Munich, Germany, acorporation of Germany Application February 28, 1952, Serial No. 274,014

13 Claims. (Cl. 179--27.5)

This invention relates to a bank contact multiple structure for switchesused in signalling systems, especially automatic telephone systems, andis particularly concerned with a bank contact multiple structurecomprising sets of continuous flat and narrow bandlike conductors bentor folded about elongated platelike insulating mounting or holdermembers to form flat spirals which extend in back of several switches,the conductors forming at the bending or folding edges of the platelikeinsulating holder members bare contact points in fixed intimateengagement with said edges, such contact points constituting bankcontacts of the corresponding switches. A structure of this type isdisclosed in copending application Ser. No. 273,847, filed February 28,1952.

The platelike insulating holder members are made of synthetic insulatingmaterial andare' disposed end to end. The insulating material used forthese holder memhers is chosen for its good dielectric property, easyworkability, elasticity and resistance against breakage. Thedisadvantage of such material is that it is subject to dimensionalchanges, due to the effect of temperature and moisture. Expansion andcontraction may cause warping of the holder members and may thus produceshunts between individual conductors or positional changes in the bankcontacts formed thereby.

The object of the invention is to provide a bank contact multiplestructure of the above indicated type in which changes in the platelikeinsulating holder members which are due to temperature or moisturefluctuations, are so controlled that they do not affect the properoperation of the associated switches.

This object is realized by the provision of means for anchoring on theframe of each switch the inner portions of the insulating holder memberscorresponding thereto, such portions facing the switch axis and carryingthe bank contacts formed by the conductors supported thereby, theanchoring being such that dimensional alterations are at the innercontact-carrying portions or edges suppressed so that such alterationscan be become eifec-' tive only in the opposite direction radiallyoutwardly away from the bank contacts where they cannot do any harm.

The invention recognizes the fact that the angular spacing between theinsulating holder members or plates increases radially rearwardly towardthe cable side of the corresponding switches, due to the radialpositioning of theh'older members relative to the switch axes, so thatexpansion and contraction can be absorbed rearwardly without harm to theinner bank contact-carrying portionsthereof. Dimensional and positionalchanges in the bank contacts, which are detrimental whether they aredirected axially or radially, are thus avoided, and the proper angularspacing between the individual bank contacts is assured and maintained.

vide a platelike insulating holder structure for securing theconductors, comprising a main plate and one or more auxiliary plates,and anchoring the bandlike narrow bank multiple conductors at the innerbank contact portions thereof on the main plate, while the rear or outerportions of such conductors are anchored on the auxiliary plate orplates, the bandlike conductors extending be tween these plates.

The platelike insulating holders can in such a structure undergo certainpositional changes without any danger of causing shunts between the barebandlike conductors.

In order to distribute dimensional changes in the platelike insulatingholder members axially of the respectively associated switch and todistribute manufacturing tolerances from a predetermined point in bothdirections, the invention provides mounting means for securing oranchoring the main plates in a median plane of the bank multiple, suchmounting means engaging a notch or recess provided on the main plates atthe bank contact side thereof. The radial anchoring or securing of themain plates is accomplished by ringlike members which are carried on theswitch frame and project into notches or recesses on the main plates atthe ends thereof. These recesses are deep enough to absorb expansion ofthe main plates axially of the switch. v

Segmentlike members having serrated edges are provided for determiningthe angular spacing between the main plates. These segmentlike membersare fixed on the vswitch frame in predetermined position, preferably atlevels coinciding with the private bank contacts thereof.

In order to. secure the main plates of the holders associated with aswitch in correct angular relationship at the rearward edges facing thewiring cables, there is provided in a median plane of the correspondingswitch a comblike dividing member which engages cutouts about centrallyof the main plates, such cutouts being formed so as to permit expansionand contraction of the main plates'in radial direction at the rear orcable wiring side thereof.

The structure and arrangement of the various mounting and anchoringmeans secures the insulating main plates of the holders at the insidethereof which faces the switch axis (bank contact side) in such a mannerthat expansion or contraction of such plates cannot become detrimentalto the bank contacts, remaining within permissible limits, and that theangular spacing between the individual insulating plates of the holdersat the rearward ends facing the wiring cables also remains withinpermissible limits. The positions of the bank contacts are definitelydetermined by the anchoring and mounting means of the invention. Theproper positions of the switch arms or wipers relative to the bankcontacts are determined by fitting means on the switch casing formounting thereon the rotary parts of the inechanism together with thedrive means therefor. These fitting means comprise suitable aligningpins and coacting bushings which are disposed in a median plane of theswitch,

, so that manufacturing tolerances can become effective in twodirections.

In. accordance with another feature of the invention, both legs of eachnarrow bandlike conductor which is wound about the insulating holderplates are fixed in proper position relative to one another. This isdone by clamping each conductor at its folding or bending edge formingthe inwardly positioned bank contacts on the corresponding main platesand by also anchoring the conductor on the auxiliary holder plates whichare disposed rearwardly at the side facing the wiring cables.

This additional securing of the positions of the bandlike conductor s'upon the insulating holder plates renders the advantage and possibilityof permitting, if needed, separation or cutting of the multiple at thewiring cable each individual conductor by a simple c ting and outwardbending thereof. The mechanical continuity of the multiple conductorband is nevertheless maintained, because the conductors are fixedly heldand properly spaced on the auxiliary insulating holder plates which aremade in the form of narrow strips.

The foregoing and additional features and objects will become ap varentfrom a description of an embodiment, which will presently be renderedwith reference to the drawings.

in these drawings,

Fig. 1 shows in diagrammatic perspective representation a switch housingand parts of the bank contact multiple provided therein;

Pig. 2 is diagrammatic sectional view taken along the switch along lineA-B of'FigJ;

Fig. 3 indicates, on an enlarged scale, asection through a main holderplate taken approximately along line FG of Fig. 2; and

Fig. 4 is a similar sectional view through an auxiliary holder platetaken approximately along the line CD of Fig. 2.

The bandlike conductors 1 are punched from fiat metallic stock and aresuitably machined to assume the form shown in Fig. 2. The insulatingholder plates 2, 25, 2-5, which are made of synthetic insulatingmaterial, hard paper or other suitable dielectric, are assembled withthe sets of conductors, while the latter are still held together by awaste strip that remained from the punching operation and are fixedlyconnected with the individual conductors, whereupon the waste parts thatremained from the punching operation are removed.

The insulating holder extending over the space occupied by one switchcomprises a main plate 2 and two auxiliary plates 25, 25', the latterbeing narrow strips or barlike members. Holes 3 are punched in the mainplate 2 for the purpose of fastening the corresponding bare bandlikeconductors 1 by means of ears formed on the conductors 1, which aredisposed in these holes and bend over to secure the correspondingconductors in place. Both legs of each conductor 1 are in this manneranchored on the main plate at the bending edge thereof which forms thebank contact.

The fastening of the bandlike conductors at the auxiliary holder plates25', 25 is accomplished by ears 26, 26 formed thereby, as shown in Fig.4.

The bandlike conductors extend over s. eyeral switches. They form themultiple cable for the associatedswitches and are mounted on theindividual switch frames after assembly wi h the insulating holderplates. Mounting means are provided to secure the insulatingholderplates in their proper positions. The main plate 2 is for thispurpose provided with a number of cutouts .for coaction with themounting means. For fixing the insulating main plates 2 r .ly of theswitch, there isprovided an armate mounting member 5 which is mounted inthe median plane of the die-cast switch frame 7 on shel flike frameportions 6. The surfaces of these portions, shown in Fig. 1 only on oneswitch side, are accurately machined so as to definitely determine theposition of the arcuate .zounting member 5. As is apparent from Fig. 2,the arcuate mounting member 5 engages a cutout 8 in each main plate 2.The depth of the cutout permits shifting f the main plates in radialdirection. 'The .areuate mounting member 5 therefore serves only .fordetermining the position of the holder main plates 1 in axial direction.Expansion and contraction of the main plates, if they occur, are by theanchoring centrally thereof by the mounting member 5 equally distributedto bothsides.

Segmental members 913 are provided for determining the angular spacingbetween the main insulating holder plates 2.

holder plates 2 at the inner bank contact sides or edges thereof. Thesesegmental members are likewise secured on portions of the framecorresponding to the shelflike portions 6 for the arcuate mountingmember 5. The segmental members are serrated, forming notches for receiving the various insulating holder plates at the inner edges thereof,and engage cutouts 14 in the insulating plates 2. These cutouts areagain formed in such a manner that they permit some displacement of theinsulating holder plates axially of the switch. The segmental member 11is fastened on the s'helflike frame portions 6 together with the arcuatemounting member 5.

The segmental anchoring members 913 thus determine the angular positionsof the main insulating However radial displacement -of the holder plates2 at the bank contact side of the switch (the bank contacts beingindicated at 15) must be prevented and there are for this purposeprovided ringlike members 17, 17' at the opposite ends of the maininsulating holder plates 2 engaging recesses 16, 15 therein, theanchoring being effected by the rims 18 of these ringlike members. Therim is shown broken away in Fig. l; The rims of the ringlike members arepointed, as indicated in Fig. l, in order to facilitate the assemblywith the other parts of the structure. The height of the rims '18permits displacement of the insulating holder plates 2 axially of theswitch but these plates are held against radial displacement.

The angular spacing between the individual insulating holder plates '2is not only secured by the segmental members 9--13, which are on theinner or bank contact side of the structure, but also by the segmentalmember 19 which is disposed at the rear of the main plates 2 and isscrew-connected with the frame parts in a median plane thereof. Thislatter segmental member 19 thus serves to maintain the angular spacingbetween the insulating holder plates 2 at the rearward edges thereofwhich face the wiring cables. Notches are provided in the segmentalmember 19 corresponding in number to the number of insulating holderplates 2.

The insulating holder plates 2 must be held in accurate positionrelative to the switch axis by the ringlike members 17, 17, and thesemembers must therefore be definitely fixed relative to .the housing 7.This is accomplished .by means of disklike members 21, 21 which securethe ringlike end members 17, 17' in .proper positions and against axialdisplacement. Screws 22 hold the disks Z1, 21 on the framepart 7.

The rotary parts of the switch, which are not shown in the drawingsextend between the recesses 23. These rotary ,parts are provided on acasing connected with the frame 7 through themedium of fittingscomprising the pins .24, 24' which determine the correct positionthereof relative to theframe 7 and the bankcontacts formed therein.These fittings are disposed in a .median plane of the. switch, .s o thatmanufacturing tolerances can be dissipated in two directions.

Fig. 2 shows ,two fastening means for the bandlike conductors 1 on theinsulating holder plate 2, which result from the displacement of thepunching tool by The manner in which the bare bandlike conductors areconnected with the insulating holder plates is apparent fromFigs. 3 and4. It will be seen from Fig. 4, which shows a section through a bandlikeconductor 1 at the side facing the wiring cable where it is folded uponitself, that the conductor is not abruptly folded about the edge of theauxiliary plates v25, 25, but is carried beyond such edge and thenpressed together. The conductors are secured on the far or rear sidefacing the wiring cable, by bending overtheears 26, 26' about theauxiliary holder plates 25, 25'. The outwardly extending free end 27' isprovided with a holefor receiving terminal means which may be solderedthereto.

In order to separate the multiple as may be desired, it is onlynecessary to cut the folded edge 27 of the conductor shown in Fig. 4 andto bend ,ap'art the two resulting conductor portions. The correspondinginsulating holder plate 25, 25' separates the two conductor portionselectricallyr W i I 1. In an automatic telephone switching device havinga frame, a plurality of holders comprising insulating mounting platesmade of material subject to deformation responsive to atmosphericinfluences, said insulating mounting plates being arranged along an arcradially of the switch axis with the inner edges thereof spaced fromsuch switch axis, each insulatingmounting, plate carrying a plurality of'bare bandlike conductors folded thereabout to form along thecorresponding inner edge a like plurality of bank contacts in fixed andintimate engagement with such inner edge, and a device for mounting saidmounting plates to counteract deformation thereof responsive toatmospheric influences so as to secure said bank contacts in theirassigned positions, said device comprising a first arcuate memberfastened to said switch frame and engaging notches in said mountingplates approximately midway between the opposite ends thereof to fixsaid mounting plates axially of 'the switch, a plurality of secondaxially spaced arcuate members mounted on said frame, the. convex edgeof each arcuate member being serrated to form notchesfor interlockingengagement with notches formed along the inner edges of said mountingplates to fix the inner edges of such mounting plates in predeterminedangular positions,-a third arcuate member mounted on said switch framein a median plane thereof andhaving serrations in; its inner concaveedge forming notches for receiving the rear ward outer edges of saidmounting plates so as to hold said outer edges in angularly spaced butradially outwardly displaceable positions, notches formed in the, topand bottom edges of said insulatingplates; arrarcuate securing membershaving peripheral rims for interlocking engagement with said top andbottom notches to hold said insulating mounting plates against radialoutward displacement but in axially outwardly displaceable positions.

2. In a bank multiple contact structure for axially successivelydisposed telephone switches or the like having fiat insulating mountingplates for each switch which are disposed along an arc radially relativeto the respective switch axis with the inner edges thereof facing suchswitch axis and carrying narrow continuous metallic bandlike conductorswhich extend from switch to switch and which are wound on saidinsulating mounting plates in fiat helical convolutions to form innerportions which are bent about the inner edges of the respectiveinsulating mounting plates in fixed engagement with such inner edges toform contacts which constitute the bank multiple contacts for suchswitch, a device for securing said insulating mounting plates to permitdimensional variations thereof due to temperature and moistureconditions to become eifective substantially radially rearwardly in adirection away from the switch axis, said device comprising firstretaining means for said insulating mounting plates for securing theinner edges of such plates in relatively fixed axial positions, secondretaining means for securing the inner edges of said insulating mountingplates in assigned angular positions, third retaining means for securingthe outer edges of said insulating mounting plates in assigned axial andangular positions while permitting radial displacement thereof, andfourth retaining means for securing the opposite ends of said insulatingmounting plates against radial displacement while permitting axialdisplacement thereof.

3. The structure defined in claim 2, comprising an auxiliary insulatingholder plate for each insulating mounting plate which is spacedtherefrom radially rearwardly in a direction away from the switch axis,said metallic bandlike conductors being wound on said insulatingmounting plate and its cooperating auxiliary holder plate.

4. The structure defined in claim 2, comprising means for anchoring eachmetallic bandlike conductor on said insulating mounting plate .in backof the inner edge thereof where such conductor forms a bank contact.

5. The structure defined in claim 2, comprising means for clamping eachmetallic bandlike conductor to said insulating mounting plate in back ofthe inner edge thereof where such conductor forms a bank contact.

6. The structure defined in claim 3, comprising means for separatelyanchoring each metallic bandlike conductor on said auxiliary insulatingholder plate and on said insulating mounting plate.

7. The structure defined in claim 2, wherein the portions of saidmetallic bandlike conductors wound about said insulating mounting platewhich are disposed rearwardly in a direction radially away from theswitch axis extend rearwardly radially spaced from the respectiveinsulating mounting plate.

8. The structure defined in claim 2, wherein said first retaining meansfor securing the inner edges of said insulating mounting plates inrelatively fixed axial positions is an arcuate member for engagementwith notches provided in said mounting plates approximately midway ofthe opposite ends thereof.

9'. The structure defined in claim 2, wherein said fourth retainingmeans comprises axially spaced members in engagement with the oppositeends of said insulating mounting plates for holding such plates againstradial displacement.

10. The structure defined in claim 2, wherein said second retainingmeans for securing the angular positions of said insulating mountingplates at the inner edges thereof facing the switch axis comprises aplurality of arcuate axially spaced members in which are formed notchesfor interlocking engagement with notches formed along the inner edges ofsaid insulating mounting members, and wherein said third retainer meansfor securing the angular positions of said insulating mounting plates atthe outer edges thereof which face radially away from the switch axis isan arcuate member in which are formed notches for engagement by theouter edges of said insulating mounting plates.

11. In a bank multiple contact structure for axially successivelydisposed telephone switches or the like having fiat insulating mountingplates for each switch which are disposed along an arc radially relativeto the respective switch axis with the inner edges thereof facing suchswitch axis and carrying narrow continuous metallic bandlike conductorswhich extend from switch to switch and which are wound on saidinsulating mounting plates in fiat helical convolutions to form innerportions which are bent about the inner edges of the respectiveinsulating mounting plates in fixed engagement with such inner edges toform contacts which constitute the bank multiple contacts for suchswitch, a device for securing said insulating mounting plates to permitdimensional variations thereof due to temperature and moistureconditions to become effective substantially radially rearwardly in adirection away from the switch axis, said device comprising firstretaining means for securing said insulating mounting plates at amidpoint of the inner edges thereof in substantially fixed positionwhile permitting limited play of the portions of said mounting plateextending from said midpoint toward the opposite ends thereof, secondretaining means for securing the inner edges of said mounting platesagainst radial play while permitting limited axial play thereof, andthird retaining means for securing said mounting plates in their angularpositions at the inner and outer edges thereof, said third retainingmeans permitting play of said mounting plates substantially onlyrearwardly in a direction away from the switch axls.

12. In a bank contact structure for telephone switches or the likehaving for each switch a plurality of fiat elongated insulating platesmade of material which is subject to dimensional changes responsive toadverse atmospheric influences, each insulating plate carrying metalliccontacts disposed along one edge thereof in fixed and intimateengagement with such edge and constituting bank contacts; a device formounting the insulating plates associated with a switch angularly spacedalong an arc with the contact-carrying edges thereof facing inwardly inradially spaced relation relative to the corresponding switch axis, saiddevice comprising first retaining means for engagement with thecontact-carrying inwardly facing edges of said insulating plates tosecure the axial positions of said edges, second retaining means forengagement with said contact-carrying edges to secure the radialpositions thereof at points intermediate the opposite ends of saidinsulating plates, and third retaining means for engagement with saidinsulating plates at the opposite ends thereof to secure the radialpositions of said icontact-carrying edges at the opposite ends of thecorresponding insulating plates, said first and second and thirdretaining means cooperating to hold the contact-carrying radiallyinwardly facing edges of saidinsulating plates against harmfuldisplacement incident to dimensional changes of the plate materialresponsive to adverse atmospheric influences so as to maintain said bankcontacts in substantially predetermined positions relative to the switchaxis.

13. in a bank contact structure for telephone switches or the likehaving for each switch a plurality of flat elongated insulating platesmade of material which is subject to dimensionalchanges responsive toadverse atmospheric influences, each insulating plate carrying metallicnarrow bandlike conductors folded thereabout to form along one edgethereof contacts in fixed and intimate engagement with such edge andconstituting bank contacts, an auxiliary insulating strip made ofsimilar material laterally spaced from the other edge of said insulatingplate with said bandlikeconductors folded about suchstrip'ftoformterminals; adevice for mounting the insulating, plates withtheirrespective insulating strips on a switch angularly spaced along an arc.with the contact-carrying edges of said plates facing inwardly'inradially spaced .relation .relative to the corresponding switch axis,said device comprising first retaining means for engagement with thecontact-carrying inwardly facing edgesoflsaid insulating :plates tosecure the axialpositions oftsaid edges, second retaining means forengagement with saidcontact-carrying edges to secure the radialpositions thereofatpoints intermediate the opposite ends of saidinsulating plates, and third retaining means for engagement .with saidinsulating plates at the opposite ends thereof to:se cure the radialpositions of said contact-carryingedgesat the opposite ends ofthecorrespondirig insulating-plates, siadfirst and second and thirdretaining means vcooperating to hold the contact-carrying radiallyinwardly -facing..edges of said insulating plates against harmfuldisplacement incident to dimensional changes of the plate materialvresponsive to adverse atmospheric influencesso as to maintain said bankcontacts in substantially predetermined positions relative to theswitchiaxis.

i.References Ctted in thefile vof this patent UNITED STATES ,PATENTS1,687,121 Bohme -Oct. 9, 1928 1,697,222 Bohme Jan. 1, 1929 2,206,325Lomax -Ju1y 2, 1940 2,239,629 Lindstrom Apr. 22, 1941 2,442,158 AndersonMay 25, 1948 O'I-HER REFERENCES "fEricsson 'Revi ew,"'No.j2, 1949, page49, Fig. 17.

